Handling of fine, wet material



Oct. 9, 1956 o. CRAIG 2,765,894

HANDLING OF FINE, WET MATERIAL Filed Oct. 28, 1952 2 Sheets-Sheet 1 INVENTOR 0/.uso/v CRAIG BY mmzgw ATTORNEY Oct. 9, 1956 Q CRAIG 2,765,894

HANDLING OF FINE, WET MATERIAL Filed Oct. 28. 1952 2 Sheets-Sheet 2 III. III/l VIII! INVENTOR OLLISON CRn/q ATTORNEY United States Patent HANDLING OF FINE, WET MATERIAL Ollison Craig, Worcester, Mass, assignor to Riley Stoker Corporation, Worcester, Mass a corporation of Massaehusetts Application October '28, 1952, Serial No. 311,331 4 Claims. (Cl. 193-2 This invention relates to the handling of fine, wet material and more particularly to apparatus arranged to transmit such material from one place to another.

In the transfer of wet, finely-ground materials from one place to another, it is often desirable or necessary to cause the material to pass through passages by using its own weight as a propellant. Such a situation occurs, for instance, in moving wet coal' from a bunker to a crusher or puiverizer. In this case the wet, fine coal packs and sticks in a vertical or an inclined spout or chute. Rapping or vibrating the chute in the usual manner merely serves to compact the coal and increases its tendency to pack and to adhere to the Walls of the chute. The present invention obviates these difliculties which have been experienced in the past in a novel manner.

it is therefore an outstanding object of this inven' tion to provide apparatus for the transfer of wet, line materials through a conduit without difiiculty due to the material packing and adhering to the walls of the conduit.

Furthermore it is an object of the invention to provide a simple, inexpensive apparatus which may be attached to the conduit for facilitating the movement of wet materials therethrough.

Another object of the present invention is the provision of apparatus for successfully moving wet coal from a storage bunker to a crushing or pulverizing means.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For abetter understanding of the invention, its operating advantages and specific objects attained "by its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Figure l is an elevational view, partially sectioned, of apparatus embodying the present invention,

Figure 2 is an elevational view of another embodiment of the invention,

Figure 3 is a view of the apparatus shown in Figure 2 and taken entire line 3-3 thereof,

Figure 4 is a vertical sectional view of another embodiment of the invention, and

Figure 5 is an elevational view, partially sectioned, of still another embodiment of the invention.

Referring "first to Figure l, a coal crusher is shown as connected to a bunker 11 by a chute 12. The crusher is of the type used before a pulverizer to crush the coal and to flash dry it. it is provided with a rotary feeder 13 and a rotor 14 having hammers 15 which crush the coal by impact. An opening 16 for the admission of warm air is provided in the housing of the crusher as well as a tramp iron pocket 17. The bunker 11 is of the usual type having a reduced lower portion to which the chute 12 is connected. A flexible bellows type connection 18 connects the bunker and the upper portion of the chute 12, while a similar connection 19 connects the lower portion of the chute 12 to the inlet of the crusher l0. Suspension rods 20 are securely fastened to the bunker 11 p r N 2765394 Patented Oct. 9, 1956 at one end and pass through openings in angle brackets 21 which are welded or otherwise fastened to the chute l2. Bolts 22 are threaded to the lower ends of the rods 20 and washers 23 overlie them. Between the washers 23 and the brackets 21 extend coil springs 24 which surround the rods and are normally under compression. It can be seen, then, that the chute 12 is resiliently suspended between the bunker and the crusher and is capable of movement therebetween. On the outer surface of the chute 12 is fastened, by welding or similar means, a mounting bracket 25 having a normally horizontal member 26 and vertical braces 27. The braces serve to support the horizontal member and to prevent movement of the bracket 25 relative to the chute 12. On the upper surface of the horizontal member is fastened an actuator comprising an electric motor 28. The motor 28 is mounted with its shaft 29 in a horizontal position and, more generally, perpendicular to the lengthwise dimension of the chute. The legs 30 of the motor are fastened to the bracket 25 in the usual manner. A disk 31 of metal is mounted eccentrically on the shaft 29 of the motor and lies in a plane perpendicular to the axis of the shaft.

In operation coal is introduced into the bunker 11. This coal may be composed of considerable fines and may be extremely wet. Electric power is introduced into the motor 28 and its shaft 29 rotates at a speed determined by the design of the motor. The rotation of the motor shaft causes a like rotation of the eccentric disk and its unbalanced weight exerts a force which is transmitted to the chute. The suspension of the chute is such that very little movement of the chute can take place in a direction perpendicular to the length of the chute, but considerable movement can take place longitudinally of the chute. The bellows type connections 18 and 19 permit such movement of the chute and the springs 24 provide a resilient means for maintaining the chute in an intermediate position during rest. The alternating unbalance of the eccentric disk 31 produces a force on the chute which is in one direction, that is to say, upward at one moment and downward at another moment. The result i that the chute is forced into a vibratory movement longitudinally of itself. Wet coal passing downwardly through the chute has -a tendency to pack and stick to the walls of the chute. However, the longitudinal movement of the chute causes -a shearing action by inertia of the coal mass between the wall of the chute and the surface of the coal at the inside surface of the chute. The coal, therefore, passes through the chute without difficulty and into the crusher '10. In the crusher it is subjected to comminution and flash-drying before passing onward to the pulverizer where it is conditioned for burning in a steam generating unit or the like.

in Figure 2 is shown an elevational view of a portion of an apparatus of the type shown in Figure l, but with certain changes in important elements. The view shows a portion of achute 32 of circular cross-section which is used for the transportation of fine, wet coal. On the chute is mounted, by welding or otherwise, a bracket 33 having a generally vertical table portion 34 and horizontal legs 35. As is evident in Figure 3, the legs 35 are formed to fit the chute 32 closely and to be securely fastened thereto. An electric motor 36 is fastened to the table portion of the bracket by means of its feet 37. The motor shaft capable of relatively limited lateral movement and relatively great longitudinal movement. The rotation of the motor shaft and the disk cause alternate forces to be thrown upon the chute whereupon it vibrates in a longitudinal direction. Such a vibration causes a shearing action between the wall of the chute and the material passing therethrough, so that the material does not stick.

in Figure 4 is shown another embodiment of the invention. A chute 40 is mounted in the manner shown in Figure l and is set in motion by means of a free-piston pneumatic motor 41. The motor consists of a piston 42 which is free to slide in a cylinder 43. The axis of the cylinder extends longitudinally of the chute and is pro vided at its ends with beads 44 and 45. The ends of the piston 42 are formed with a spherical surface which contacts one of the heads at the end of its stroke. Air under pressure is admitted to the ends of the cylinder through ports 46 and 47 which are connected to ports 48 and 49, respectively, of a pilot valve 50. The ports 48 and 49 enter a cylinder 51 forming a part of the pilot valve and the flow of air in and out of these ports is controlled by the movement of a spool 52 which reciprocates in the cylinder. The spool 52 is connected at one end to a rod 53 having a cam shoe 54 at its outer end. The cam shoe engages an eccentric cam 55 which is keyed to a rotatable shaft 56. The cam shoe is caused to follow the cam 55 at all times by a spring 57 which is compressed between the shoe and the valve housing. Air under pressure is admitted to the cylinder 51 through a conduit 58 situated centrally thereof, while conduits 59 and 60 permit air to pass in and out of the cylinder at points adjacent the ends thereof. During operation, the chute 40 is mounted for longitudinal motion and the fine, wet material passes downwardly through it. Air under pressure is admitted to the pilot valve 50 through the conduit 58. The shaft 56 is rotated by means of a small electric motor or the like and causes the spool 52 to reciprocate, thus causing the air to enter one end of the cylinder 43 while exhausting from the other end. Air under pressure, therefore, is admitted first to one end of the piston 42 and then to the other, causing it to reciprocate in the cylinder 43. The length of stroke of the piston 42 is selected, by proper design so that it contacts one of the cylinder heads before moving in the other direction. The force of the impact of the piston against the head is transmitted to the chute, since the motor 41 is securely attached thereto. The resulting motion of the chute causes a shearing action between the inside surface of the chute and the material passing therethrough thus preventing sticking or bridging.

Figure shows another embodiment of the invention which makes use of an electromagnetic actuator for moving the chute. A chute 61 is mounted in the abovedescribed manner and to its side is fastened, by welding or otherwise, an armature such as an iron abutment 62 having a broad face 63 which extends transversely of the chute. Adjacent the abutment, but supported independently of the chute, is a channel bwm 64 to which is fastened an electromagnet 65. The electromagnet has an iron core 66 which is threaded at one end. This threaded end extends through the channel 64 and is held thereon by a nut 67. The other end of the core is situated adjacent the face 63 of the abutment. The core is generally elongated and extends parallel to the chute. On the core is wound a long coil 68 of insulated wire the ends of which are connected to a source 69 of alternating current electricity. In the operation of the apparatus, the chute is caused to vibrate longitudinally, whereupon even very fine, wet material passes through the chute with case.

The natural frequency of the resiliently suspended chute and the frequency of the peaks of energization of the elec tromagnet must be selected with care to obtain optimum results. For instance it has been found that the natural frequency of the chute suspension should be slightly higher than the pulsating energization of the magnet. In some cases it may be desirable to use pulsing current in the coil of the magnet, rather than alternating.

While in accordance with the provisions of the statutes I have illustrated and described herein the best forms of my invention now known to me, those skilled in the art will understand from the spirit of the invention covered by my claims that certain features of my invention may sometimes be used to advantage without a cor responding use of other features.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An apparatus for the transportation of finely-divided material by gravity from an upper source of supply to a lower point of discharge comprising an elongated chute, a resilient support maintaining the said chute in a generally vertical position joining the source to the said point, said support comprising rods extending downwardly from the said upper source, an abutment extending laterally from the upper end of the chute in closely adjacent relationship to each rod, and spring means fastened to and extending between each rod and its abutment, a flexible conduit connecting the source to the upper end of the chute, a second flexible conduit connecting the point of discharge to the lower end of the chute and an actuator operatively connected to said chute, said actuator causing the chute to reciprocate principally in the direction of its length.

2. An apparatus as recited in claim 1 wherein the actuator consists of an electric motor mounted on the chute with its shaft extending transversely thereof and an cecentric disk mounted on the said shaft with its plane perpendicular to the shaft.

3. An apparatus as recited in claim 1 wherein the actuator consists of a pneumatic motor mounted on the chute, said motor having a free piston which moves longitudinally of the chute and a pilot valve which admits air alternately to opposite ends of the piston for the actuation thereof.

4. An apparatus as recited in claim 1 wherein the actuator consists of an electro-magnet mounted independently of the chute, and an armature mounted on the chute, the line of attraction between the electro magnet and the armature being lengthwise of the chute.

References Cited in the file of this patent UNITED STATES PATENTS 890,190 Stephens June 9, 1908 1,028,577 Lucking June 4, 1912 1,063,902 Anderson June 3, 1913 1,407,211 Miner Feb. 21, 1922 1,923,678 Lowell Aug. 22, 1933 1,932,520 Horsch Oct. 31, 1933 2,164,483 Watson et al. July 4, 1939 2,175,541 Probert Oct 10, 1939 2,533,331 Skinner Dec. 12, 1950 2,535,127 Frei Dec. 26, 1950 2,549,033 Tyrner Apr. 17, 1951 2,551,984 Walton May 8, 1951 2,609,791 Bohlman Sept. 9, 1952 FOREIGN PATENTS 384,338 Germany Sept. 27, 1921 826,523 Germany Jan. 3, 1952 

